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From:Andrew Armstrong Date:August 4 2007 4:17am
Subject:RE: How can I delete a block of random rows?
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Are you sure you want to delete random rows, or do you (if you have
sequential IDs) just want to delete every n'th row?

DELETE FROM table WHERE id MOD 5 = 0

Delete every 5th row from the table assuming sequential IDs with no missing
numbers.

Something like that anyway.

-----Original Message-----
From: Baron Schwartz [mailto:baron@stripped] 
Sent: Saturday, 4 August 2007 12:41 PM
To: Daevid Vincent
Cc: 'MySQL General'
Subject: Re: How can I delete a block of random rows?

Daevid Vincent wrote:
> I have a SQL dump that I load in for testing with lots of "interesting"
> data.
>  
> I want to now pair that down to a smaller subset, however I can't just
> delete from a range of ID's, as the data is sequential.
>  
> I want to delete say 1000 random rows from the table.

What fraction of the rows do you want to delete? 1%?

DELETE FROM TABLE WHERE RAND() < .01;

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Thread
How can I delete a block of random rows?Daevid Vincent4 Aug
  • Re: How can I delete a block of random rows?Baron Schwartz4 Aug
    • RE: How can I delete a block of random rows?Andrew Armstrong4 Aug
      • RE: How can I delete a block of random rows?Daevid Vincent6 Aug